The present invention relates to an ionic metal complex having a novel chemical structure and a process for synthesizing the ionic metal complex that is used as a supporting electrolyte for lithium batteries, lithium ion batteries, electrical double-layer capacitors and other electrochemical devices, a polymerization catalyst for polyolefins and so forth, or a catalyst for organic synthesis.
Ionic complexes, such as PF6xe2x88x92, BF4xe2x88x92 and AsF6xe2x88x92, formed by bonding of Lewis acids with F ion have been used in applications such as supporting electrolytes for electrochemical devices, polymerization catalysts for polyolefins and so forth or catalysts for organic synthesis due to their solubility and ion dissociation characteristics.
As the application range of these ionic complexes becomes increasingly diverse, efforts are being made to search for the optimum ionic complex for each application, and these ionic complexes are being required to have properties including heat resistance, hydrolysis resistance, low toxicity and recycleability.
It is an object of the present invention to provide a useful, novel, ionic metal complex and a process for synthesizing the same.
As a result of earnest studies, the inventors of the present invention found an ionic metal complex having a novel chemical structure and a process for synthesizing the same, thereby leading to completion of the present invention.
According to the present invention, there is provided an ionic metal complex represented by the general formula (1): 
wherein M is a transition metal selected from the group consisting of elements of groups 3-11 of the periodic table, or an element selected from the group consisting of elements of groups 12-15 of the periodic table; Aa+ represents a metal ion, onium ion or proton; provided that M is not B when Aa+ is Cs+; a represents a number from 1 to 3; b represents a number from 1 to 3; p is b/a; m represents a number from 1 to 3; n represents a number from 0 to 4; q is 0 or 1; X1 represents O, S or NR5R6; each of R1 and R2 independently represents H, a halogen, a C1-C10 alkyl group or C1-C10 halogenated alkyl group; R3 represents a C1-C10 alkylene group, C1-C10 halogenated alkylene group, C4-C20 aryl group or C4-C20 halogenated aryl group; R4 represents a halogen, C1-C10 alkyl group, C1-C10 halogenated alkyl group, C4-C20 aryl group, C4-C20 halogenated aryl group or X2R7; X2 represents O, S or NR5R6; each of R5 and R6 represents H or a C1-C10 alkyl group; and R7 represents a C1-C10 alkyl group, C1-C10 halogenated alkyl group, C4-C20 aryl group or C4-C20 halogenated aryl group.
According to the present invention, there is provided a first process for synthesizing the ionic metal complex. The first process comprises reacting a compound represented by the general formula (2) with a metal complex represented by the general formula (3). This compound contains at least two active hydrogens. 
wherein X1, R1, R2, R3, R4, M, Aa+, q, a, b, p, m, and n are defined as above, R8 represents a halogen, hydroxyl group, hydrogen, C1-C10 alkyl group, C1-C10 halogenated alkyl group, C4-C20 aryl group, C4-C20 halogenated aryl group or X3R9; X3 represents O, S or NR5R6 where R5 and R6 are defined as above; and R9 represents a C1-C10 alkyl group, C1-C10 halogenated alkyl group, C4-C20 aryl group or C4-C20 halogenated aryl group.
According to the present invention, there is provided a second process for synthesizing the ionic metal complex. The second process comprises (a) reacting a first compound represented by the general formula (2) with a metal complex represented by the general formula (4), thereby obtaining an intermediate; and (b) reacting the intermediate with a second compound, thereby obtaining the ionic metal complex. The first compound contains at least two active hydrogens. The second compound contains a cation represented by Aa+ defined as above and is selected from the group consisting of metal halides, metal alkoxides, metal carboxylates, metal hydroxides, metal oxides, metal carbonates, quaternary alkylonium halides, quaternary alkylonium hydroxides and quaternary alkylonium carboxylates. 
wherein X1, R1, R2, R3, R4, R8, M, q, m, and n are defined as above.
According to the present invention, there is provided a third process for synthesizing the ionic metal complex. The third process comprises (a) reacting a first compound represented by the general formula (2) with a second compound containing an alkali metal or alkali-earth metal, thereby obtaining an intermediate; and (b) reacting the intermediate with a metal complex represented by the general formula (5), 
wherein X1, R1, R2, R3, R4, M, Aa+, q, a, b, p, m, and n are defined as above, R10 represents a halogen or hydroxyl group.
The above-mentioned ionic metal complex has a novel chemical structure and can be used as a supporting electrolyte for lithium batteries, lithium ion batteries, electrical double-layer capacitors and other electrochemical devices, a polymerization catalyst for polyolefins and so forth, or a catalyst for organic synthesis. The ionic metal complex can be synthesized by each of the above-mentioned first, second and third processes.
According to the invention, the alkyl groups, halogenated alkyl groups, aryl groups and halogenated aryl groups, which are contained in the ionic metal complex and the raw materials for synthesizing the same, may be branched and/or may have other functional groups such as hydroxyl groups and ether bonds.
The followings are specific nine examples of the ionic metal complex represented by the general formula (1) of the present 
Here, although lithium ion is indicated as an example of Aa+ of the general formula (1), examples of other cations that can be used other than lithium ion include sodium ion, potassium ion, magnesium ion, calcium ion, barium ion, cesium ion, silver ion, zinc ion, copper ion, cobalt ion, iron ion, nickel ion, manganese ion, titanium ion, lead ion, chromium ion, vanadium ion, ruthenium ion, yttrium ion, lanthanoid ion, actinoid ion, tetrabutylammonium ion, tetraethylammonium ion, tetramethylammonium ion, triethylmethylammonium ion, triethylammonium ion, pyridinium ion, imidazolium ion, proton, tetraethylphosphonium ion, tetramethylphosphonium ion, tetraphenylphosphonium ion, triphenylsulfonium ion, triethylsulfonium ion and triphenylmethyl ion. In the case of considering the application of the ionic metal complex for electrochemical devices and the like, lithium ion, tetraalkylammonium ion and proton are preferable. In addition, in the case of the application of the ionic metal complex for catalyst, lithium ion, proton, triphenylmethyl ion, trialkylammonium ion and metallocenium ion are preferable. As shown in the general formula (1), the valency (valence) of the Aa+ cation is preferably from 1 to 3. If the valency is larger than 3, the problem occurs in which it becomes difficult to dissolve the ionic metal complex in solvent due to the increase in crystal lattice energy. Consequently, in the case of requiring solubility of the ionic metal complex, a valency of 1 is preferable. As shown in the general formula (1), the valency (bxe2x88x92) of the anion is similarly preferably from 1 to 3, and a valency of 1 is particularly preferable.
The constant p expresses the ratio of the valency of the anion to the valency of the cation, namely b/a.
In the general formula (1), M at the center of the ionic metal complex of the present invention is selected from elements of groups 3-15 of the periodic table. It is preferably Al, B, V, Ti, Si, Zr, Ge, Sn, Cu, Y, Zn, Ga, Nb, Ta, Bi, P, As, Sc, Hf or Sb, and more preferably Al, B or P. Although it is possible to use various elements for the M other than these preferable examples, synthesis is relatively easy in the case of using Al, B, V, Ti, Si, Zr, Ge, Sn, Cu, Y, Zn, Ga, Nb, Ta, Bi, P, As, Sc, Hf or Sb. In addition to ease of synthesis, the ionic metal complex has excellent properties in terms of low toxicity, stability and production cost in the case of using Al, B or P.
In the general formula (1), the organic or inorganic portion bonded to M is referred to as the ligand. As mentioned above, X1 in the general formula (1) represents O, S or NR5R6, and is bonded to M through its hetero atom (O, S or N). Although the bonding of an atom other than O, S or N is not impossible, the synthesis becomes extremely bothersome. The ionic metal complex represented by the general formula (1) is characterized by these ligands forming a chelate structure with M since there is bonding with M by a carboxyl group (xe2x80x94COOxe2x80x94) other than X1 within the same ligand. As a result of this chlelation, the heat resistance, chemical stability and hydrolysis resistance of the ionic metal complex are improved. Although constant q in this ligand is either 0 or 1, in the case of 0 in particular, since the chelate ring becomes a five-member ring, chelating effects are demonstrated most prominently, making this preferable due to the resulting increase in stability. In addition, since the negative charge of the central M is dissipated by electron attracting effects of the carboxyl group(s) resulting in an increase in electrical stability of the anion, ion dissociation becomes extremely easy resulting in corresponding increases of the ionic metal complex in solvent solubility, ion conductivity, catalyst activity and so forth. In addition, the other properties of heat resistance, chemical stability and hydrolysis resistance are also improved.
In the general formula (1), each of R1 and R2 is independently selected from H, halogen, C1-C10 alkyl groups and C1-C10 halogenated alkyl groups. At least one of either R1 and R2 is preferably a fluorinated alkyl group, and more preferably, at least one of R1 and R2 is a trifluoromethyl group. Due to the presence of an electron-attracting halogen and/or a halogenated alkyl group for R1 and R2, the negative charge of the central M is dissipated. This results in an increase of the anion of the general formula (1) in electrical stability. With this, the ion dissociation becomes extremely easy resulting in an increase of the ionic metal complex in solvent solubility, ion conductivity, catalyst activity and so forth. In addition, other properties of heat resistance, chemical stability and hydrolysis resistance are also improved. The case in which the halogen is fluorine in particular has significant advantageous effects, while the case of a trifluoromethyl group has the greatest advantageous effect.
In the general formula (1), R3 is selected from C1-C10 alkylene groups, C1-C10 halogenated alkylene groups, C4-C20 aryl groups and C4-C20 halogenated aryl groups. R3 is preferably one which forms a 5 to 10-membered ring when a chelate ring is formed with the central M. The case of a ring having more than 10 members is not preferable, since chelating advantageous effects are reduced. In addition, in the case R3 has a portion of hydroxyl group or carboxyl group, it is possible to form a bond between the central M and this portion.
In the general formula (1), R4 is selected from halogens, C1-C10 alkyl groups, C1-C10 halogenated alkyl groups, C4-C20 aryl groups, C4-C20 halogenated aryl groups and X2R7. Of these, fluorine is preferable. X2 represents O, S or NR5R6 and bonds to M through one of these heteroatoms (O, S and N). Although the bonding of an atom other than O, S or N is not impossible, the synthesis becomes extremely bothersome. Each of R5 and R6 is selected from H and C1-C10 alkyl groups. Each of R5 and R6 differs from other groups (e.g., R1 and R2) in that the former is not required to be an electron attracting group. In the case of introducing an electron attracting group as R5or R6, the electron density on N of NR5R6 decreases, thereby preventing coordination on the central M. R7 is selected from C1-C10 alkyl groups, C1-C10 halogenated alkyl groups, C4-C20 aryl groups and C4-C20 halogenated aryl groups. Of these, a C1-C10 fluorinated alkyl groups is preferable. Due to the presence of an electron-attracting halogenated alkyl group as R7, the negative charge of the central M is dissipated. Since this increases the electrical stability of the anion of the general formula (1), ion dissociation becomes extremely easy resulting in an increase of the ionic metal complex in solvent solubility, ion conductivity and catalyst activity. In addition, other properties of heat resistance, chemical stability and hydrolysis resistance are also improved. The case in which the halogenated alkyl group as R7 is a fluorinated alkyl group in particular results in even greater advantageous effects.
In the general formula (1), the values of the constants m and n relating to the number of the above-mentioned ligands depend on the type of the central M. In fact, m is preferably from 1 to 3, while n is preferably from 0 to 4.
Next, the following provides an explanation of the process for synthesizing the ionic metal complex of the present invention. As a result of earnest studies, the synthesis process broadly divided into three types (i.e., the above-mentioned first, second and third processes) were found to obtain the target compound, the ionic metal complex.
As stated above, the first process for synthesizing the ionic metal complex comprises reacting a compound represented by the general formula (2) with a metal complex represented by the general formula (3). Symbols other than R8 in the general formulas (2) and (3) are the same as those of the general formula (1). In fact, R8 is selected from halogens, hydroxyl group, hydrogen atom, C1-C10 alkyl groups, C1-C10 halogenated alkyl groups, C4-C20 aryl groups, C4-C20 halogenated aryl groups and X3R9. Furthermore, R9 is selected from C1-C10 alkyl groups, C1-C10 halogenated alkyl groups, C4-C20 aryl groups and C4-C20 halogenated aryl groups, and X3 is O, S or NR5R6.
Mixing 1 mole of the compound represented by the general formula (2) with 1/m moles, where m is defined as in the general formula (3), of the metal complex represented by the general formula (3) results in addition of the active hydrogens (i.e., hydrogens respectively bonded to X1 and O in the general formula (2)) of the compound of the general formula (2) to R8 of the general formula (3), followed by dissociation in the form of R8H. With this, the target ionic metal complex of the general formula (1) is obtained.
As stated above, the second process for synthesizing the ionic metal complex comprises:
(a) reacting a first compound represented by the general formula (2) with a metal complex represented by the general formula (4), thereby obtaining an intermediate; and
(b) reacting the intermediate with a second compound, thereby obtaining the ionic metal complex.
The first compound contains at least two active hydrogens, as shown in the general formula (2). The second compound contains a cation represented by Aa+ that is a metal ion or onium ion. The second compound is selected from the group consisting of metal halides, metal alkoxides, metal carboxylates, metal hydroxides, metal oxides, metal carbonates, quaternary alkylonium halides, quaternary alkylonium hydroxides and quaternary alkylonium carboxylates. The symbols used in the formulas (2) and (4) are the same as those used in the general formulas (1) and (3). Mixing 1 mole of the first compound of the general formula (2) with 1/m moles of the second compound of the general formula (4) results in addition of the active hydrogens of the first compound of the general formula (2) to R8 of the general formula (4), followed by dissociation in the form of R8H. However, the number of R8, that is, xe2x80x9c2mxe2x88x921xe2x80x9d is deficient by one in the general formula (4), as compared with the number of active hydrogens in the general formula (2). Therefore, the surplus active hydrogen turns into a hydrogen ion (proton), and another active hydrogen that has formed a pair with the surplus active hydrogen is bonded to M. With this, there is obtained an intermediate represented by the general formula (1) wherein Aa+ is the proton. Then, this intermediate is reacted with the second compound containing Aa+ that is a metal ion or onium ion to conduct an ion-exchange between the proton of the intermediate and Aa+ of the second compound, thereby obtaining the ionic metal complex.
As stated above, the third process for synthesizing the ionic metal complex comprises:
(a) reacting a first compound represented by the general formula (2) with a second compound containing an alkali metal or alkali-earth metal, thereby obtaining an intermediate; and
(b) reacting the intermediate with a metal complex represented by the general formula (5).
Symbols in the formulas (2) and (5) are the same as those of the general formula (1) with the exception of R10. In fact, R10 represents a halogen or hydroxyl group. By the step (a), active hydrogens of the first compound in an amount of 1 mole can be replaced with the alkali metal or alkali-earth metal of the second compound. The resulting intermediate can be mixed with the metal complex in an amount of 1/m moles to conduct the step (b). With this, the alkaline metal or alkaline earth metal ions of the intermediate are added to R10 of the metal complex, followed by dissociation of the alkaline metal salt or alkaline earth metal salt of R10 having low solubility in the form of precipitate. Thus, the target ionic metal complex of the general formula (1) is obtained.
Solvent can be used in the above-mentioned first, second and third processes, and it is not particularly limited as long as it can dissolve the raw materials even in minute amounts. The solvent is preferably an inert solvent, which does not react with compounds in the reaction system. Furthermore, the solvent is preferably one having a dielectric constant of at least 2. The use of a solvent having no dissolving power whatsoever is not preferable, since the reaction proceeds extremely slowly. Even if the solvent has only slight solubility, since the solubility of the target ionic metal complex is extremely large, the reaction proceeds rapidly. Examples of the solvent that can be used in the first, second and third processes include carbonates, esters, ethers, lactones, nitriles, amides, sulfones, alcohols and aromatics, and these solvents can either be used alone or in the form of a mixed solvent of two or more types. Specific examples of the solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methylethyl carbonate, dimethoxyethane, acetonitrile, propionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, nitromethane, N,N-dimethylformamide, dimethylsulfoxide, sulfolane, xcex3-butyrolactone, toluene, ethanol, methanol and water.
The first, second third processes can be conducted at a reaction temperature of xe2x88x9280xc2x0 C. to 100xc2x0 C., preferably 0xc2x0 C. to 80xc2x0 C. The reaction may not proceed sufficiently at a temperature lower than xe2x88x9280xc2x0 C. Decomposition of the raw materials may occur at a temperature above 100xc2x0 C. A temperature range of 0xc2x0 C. to 80xc2x0 C. is optimum in order to obtain a sufficient reaction rate while also preventing the occurrence of decomposition.
Since many of the raw materials used in the first, second and third processes are hydrolytic, it is preferable to carry out them in an atmosphere of air, nitrogen or argon and so forth having a low moisture content.